This Center is part of the Cooperative Aneurysm Study. The Albert Einstein College of Medicine, Departments of Neurological Surgery and Neurology have been part of the Aneurysm Study Group for the past seven years. Under its current Chairman of the Department of Neurosurgery it has been active in the present phase of the study. The Department activities are based in a large urban area servicing a primarily middle to lower class patient population with a large representation of people of the black race and of Spanish origins. Patients for the study are admitted to the Bronx Municipal Hospital Center or Montefiore Hospital or the Hospital of the Albert Einstein College of Medicine. In the past we have admitted approximately 30 patients each year for randomization under the cooperative protocol. Our patients tend to be relatively young in age, and because our department provides emergency service, they are admitted very shortly after their primary subarachnoid hemorrhage. This allows early entry into the protocol and allows careful management of the acute episode as well as subsequent rebleeds. In the past, the program has been largely based within the Department of Neurosurgery with the close and cordial relations with the Department of Neurology and the Section of Neuroradiology of the Department of Biology. This administrative structure will be maintained.